Abstract: The effect of sweet potato residue treated by steam explosion (SE-SPR) on wheat dough properties and quality characteristics of cookies was studied. The sedimentation index, starch gelatinization properties and farinographical characteristics of wheat flour mixed with different proportions of SE-SPR and the texture properties of cookies made from their mixtures were measured instrumentally. The results showed that the sedimentation index of wheat flour and the peak viscosity, trough viscosity, breakdown, final viscosity and setback of wheat starch paste were decreased with the addition of SE-SPR. The addition of SE-SPR to wheat flour resulted in dilution of gluten. Accordingly, increasing soluble dietary fiber content increased the water-absorbing capacity, reduced dough development and stability time, increased dough softening degree, and decreased farinograph quality number. Furthermore, the texture properties of the cookies made from the mixture were changed as compared with those of pure wheat cookies. According to texture properties and sensory evaluation, the quality of cookies made from low-gluten flour with 6% (m/m) SE-SPR added was best.

Key words: sweet potato residue treated by steam explosion, wheat flour, farinographical characteristics, cookies